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Orientador: Stephenson Caticha-Ellis Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin Resumo: Neste trabalho é utilizada a técnica de difração múltipla de raios-X no estudo da concentração e localização de impurezas na rede cristalina, acrescida da observação fundamental de que as impurezas não podem estar distribuídas com a mesma simetria do grupo espacial do cristal. Isto em princípio, poderia fazer aparecer intensidade espalhada nos nós proibidos da rede recíproca do cristal. Esse efeito foi efetivamente observado em diagramas de difração múltipla, onde através da escolha adequada das reflexões envolvidas, produz-se um reforço na intensidade espalhada nas posições proibidas para o cristal puro, porém observáveis no dopado. Foi desenvolvida a teoria das refletividades no caso cinemático que leva em conta o espalhamento pelos átomos de impurezas, cuja análise mostrou, em primeira aproximação, que a influência das impurezas pode se dar tanto nas posições permitidas para o cristal puro quanto nas proibidas, sendo que nas primeiras pode-se em princípio, obter informação sobre a posição e nas últimas, sobre a concentração das mesmas. A aplicação dessa teoria no caso da difração múltipla de raios-x forneceu subsídios para a escolha das posições de medida (reflexões múltiplas). Seu estudo analítico feito em aproximações de segunda e terceira ordens, resultou na escolha de casos de três feixes tipo Bragg-Bragg com ambas reflexões proibidas com acoplamento forte o caso mais favorável para o estudo da concentração. Ambos os casos Bragg-Bragg e Bragg~Laue, com reflexão secundária permitida são adequados ao estudo da localização das impurezas. Porém a sensibilidade varia muito segundo as reflexões envolvidas. Além disso, também é apresentada nesse trabalho, uma nova contribuição ao uso da difração múltipla com a escolha de um vetor primário proibido e sem simetria, o que produz várias vantagens, entre elas: discriminação por observação direta dos chamados pares de Bijvoet, desacoplamento dos casos de quatro feixes simultâneos transformando-os em casos de três feixes, uma indexação em forma absoluta usando apenas um espelho de simetria em diagramas de difração múltipla, assim como a possibilidade de se medir numa ou duas experiências a maior parte dos fatores de estrutura já corrigidos por absorção, Lorentz, polarização e extinção, fornecendo assim um método novo para medidas destinadas à resolução de estruturas. Sendo que a maior dificuldade experimental reside em que é necessário medir intensidades extremamente fracas, é preciso usar fontes geradoras de raios-X de alta potência. As experiências foram realizadas com um Rotaflex (ânodo rotatório) com alvo de Cu, no qual foram feitas várias adaptações para permitir as medidas pretendidas. Contudo a fonte aconselhável para esta experiência seria um síncroton. As amostras utilizadas foram placas cristalinas de Si puro e dopadas com Au e Sb, cortadas na direção [111] e também rutilo (TiO2) cortado na direção [201] proibida pelo grupo espacial e sem simetria especial, para usar a nova técnica de desacoplamento. Os resultados experimentais foram analisados através dos gráficos da relação R=[(sinal/ruído)dop]/[(sinal/ruído)puro] em função a concentração atômica (Au e Sb) para diferentes posições desses átomos na rede do Si. O fato importante a ser ressaltado é que a cada tipo de posição corresponde uma curva diferente no intervalo de concentrações possíveis, o que possibilita a sua discriminação. No caso do rutilo são mostrados diagramas de difração múltipla mostrando claramente o efeito de desacoplamento e indexação absoluta Abstract: Not informed Doutorado Física Doutor em Ciências

Agradecimentos: Ana Paula Badan Ribeiro thank CNPq (303429/2018-6) for productivity grant and São Paulo Research Foundation-FAPESP (16/11261-8). Kamila Ramponi Rodrigues de Godoi thank CNPq (140789/2017-0) for PhD scholarship grant. Lisandro Pavie Cardoso thank CNPq (302626/2016-6 and 307896/2019-6) for productivity grant. This study was financed in part by the "Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brazil (CAPES)"–Finance Code 001 Abstract: In this work, we studied the influence of fatty acid chain length and crystallization temperature on the crystallization behavior during the storage of binary blends modified by chemical interesterification. The blends were produced with soybean oil and fully hydrogenated oils from palm kernel, palm, soybean, microalgae, and crambe, evaluated separately, at a ratio of 50:50 (% w/w). The blends were crystallized by two crystalline stabilization methods. In method I, the samples were maintained at 25 ? for 24 h before the analyses. In method II, the samples were maintained at 5 ? for 24 h, followed by crystalline stabilization at 25 ? for 24 h before the analyses. The interesterification reaction caused considerable changes in the TAGs profile with increasing asymmetric TAGs. These TAGs changes promoted an increase in the crystallization induction time, a decrease in the maximum solids content, and changes in crystals morphology. The increase in the FAs chain length promoted the increased nucleation rate that influenced morphology crystals. Method II promoted a reduction in the me-dium diameter of crystals and the appearance of the 13 phase with storage time. For crystallization carried out at higher temperatures (method I), we observed that 13' was favored. Unusual polymorphic transitions were observed with storage time in samples with higher tristearin content. We identified clear correlations between the predominance of 13' phase in the interesterified blends and TAGs of S2U and SU2-type. In addition, the blends with a more diverse range of fatty acids concerning chain size also showed the 13' polymorph. 13 polymorph, on the other hand, was associated with symmetric TAGs, S3 and U3, and CN-54 type TAG. In this study, we used the Rietveld method to quantify the polymorphs and amorphous content in the blends before and after the randomization reaction. This approach allowed a deeper understanding of the crystalline behavior in the blends, which would be difficult to achieve by performing only a visual analysis of the X-ray diffractograms CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: Ana Paula Badan Ribeiro thank Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq, Brazil (grant number 303429/2018-6) for productivity grant and Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP, Brazil (grant number 16/11261-8. Kamila Ramponi Rodrigues de Godoi thank Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq, Brazil (grant number 140789/2017-0) for PhD scholarship grant. Lisandro Pavie Cardoso thank Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq, Brazil (grant numbers 302626/2016-6 and 307896/2019-6) for productivity grant. This study was financed in part by the "Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brazil (CAPES)"–Finance Code 001 Abstract: The objective of this study was to develop new nanostructured lipid carrier (NLC) formulations loaded with free phytosterols (FPs) using interesterified and simple lipid phases. The simple and interesterified lipid phases were composed of soybean oil as liquid lipid and fully hydrogenated palm (HPO) and crambe (HCO) oils s solid lipids. High-pressure homogenization was the preparation method, with soy lecithin as a natural emulsifier. The characteristics of NLCs were influenced by chemical interesterification and the composition of solid lipid, mainly with respect to the fatty acid chain size. All developed FP-loaded NLCs displayed an appropriate nanoscale size from approximately 167 to 330 nm (d(32)) and appropriate physical stability with zeta potential values ranging from -29.83 to -43.70 mV after 30 days of storage. The changes observed in these parameters were influenced by the lipid phase of the NLCs and the crystallization of FP on the surface of the NLCs. FP-loaded NLCs formulated with interesterified blends displayed smaller particle size values, with less evidence of particle agglomeration and higher absolute zeta potential values than NLCs formulated with simple blends. These results indicated that NLCs developed with interesterified lipid blends were more stable than those developed with single blends NLCs produced from solid lipids with fatty acids with larger chain sizes (HCO) had larger particle sizes but were less likely to flocculate and coalesce. Thermal behavior study revealed that interesterification caused a reduction in the melting temperature and recrystallization index of the NLCs. These findings indicated decreased crystallinity and a less organized structure. This behavior favored the highest encapsulation efficiency and load capacity observed for NLCs developed with interesterified blends CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

As an alternative to the strategies currently used to deliver unsaturated fatty acids, especially, the essentials omega-6 and 3- fatty acids, the aim of this work was to investigate the effect of the incorporation of 25 e 50% (w/w) of olive, corn and linseed oil into the crystal structure of anhydrous milk fat (AMF). Fatty acid composition, atherogenicity (AI), and thrombogenicity (TI) index, crystallization kinetics, polymorphism by Rietveld method (RM), microstructure, thermal behavior, solid fat content, and lipid compatibility was evaluated. The addition of vegetable oils reduced the saturated fatty acids, and the AI and TI indices of AMF, and increased the concentration of unsaturated, specifically omega-6 and -3 fatty acids. Although vegetable oils caused changes in nucleation and crystallization kinetics, the spherulitic and crystalline morphology and the beta' polymorphism of AMF were maintained. The study demonstrated the possibility of using the crystal structure of AMF as a vehicle for unsaturated fatty acids in food formulations, as an alternative to nutritional supplementation. In addition, studies on the use of RM in blends made with AMF and vegetable oil have not been found in literature, thus demonstrating the relevance of the present study COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Organogels are semi-solid systems where the liquid phase is immobilized for three-dimensional network self-sustained formed by structuring agents capable to hold a larger quantity of liquid oil. The use of these structuring agents or crystallization modifiers, as specific triacylglycerols, emulsifiers and high molecular weight - high melting point lipids, have been recognized as the main alternative for obtaining low saturated fats for food formulation. The aim of this work was to evaluate the crystallization, microstructure and polymorphism properties of hybrid soybean oil (SO) organogels, formulated with 6% (w:w) of structuring agents through a centroid simplex system added singly, in binary or ternary association of candelilla wax (CW), sorbitan monostearate (SMS) and fully hydrogenated palm oil (FHPO). The thermal behavior, crystallization kinetics, physical stability by temperature cyclization, microstructure and polymorphism were evaluated. FHPO and CW increased the stability and ability to form crystalline networks in organogels, while SMS accelerated the crystallization process. The structuring agents increased the initial and final crystallization temperatures, even as the melting temperatures and the enthalpy values of organogels. Time-temperature cyclization (cyclization 1: 5 degrees C/48 h + 35 degrees C/24 h + 5 degrees C/24 h; cyclization 2: 35 degrees C/48 h + 5 degrees C/72 h) showed that all the systems resulted in firm and stable organogels, except when SMS or FHPO were used singly. CW promoted formation of denser crystalline networks with higher solids content, quick crystallization onset and higher melting points that indicates adequate thermal resistance; while FHPO increased the solid content although it was effective to obtain organogels only at the cooling temperature (5 degrees C). The binary interaction of FHPO + CW increased the thermal resistance of organogels; and the interactions among SMS + CW and SMS + CW + FHPO although it was effective to obtain organogels. Regardless of the presence and proportions of structuring agents, organogels were characterized by beta polymorphism COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

RMn2Si2 (R = Tm, Dy, and Tb) and HoCoSi alloys, presenting multiple magnetic phase transitions (except for TmMn2Si2 and HoCoSi) and large magnetocaloric effect (MCE), were physically mixed to produce a composite magnetic refrigerant. The used concentration of each alloy was 0.1(TmMn2Si2) + 0.35(DyMn2Si2) + 0.4(TbMn2Si2) + 0.15(HoCoSi). X-ray diffraction and magnetization measurements were used to investigate the crystallographic and magnetic properties of the samples. The results indicate the maximum values of magnetic entropy change (-Delta s(M)(max)) of similar to 4.6 J/kgK undermagnetic field change (Delta H) of 50 kOe. A large table-like MCE was observed for the composite sample. The full width at half maximum of Delta S-M peak (delta T-FWHM) values reaches similar to 60.4 K (Delta H = 20 kOe) and similar to 67.2 K (Delta H = 50 kOe), which correspond to a respective. Delta S-M peak broadening of 230% and 180% for the composite sample compared with each compound studied individually. Such property is important for a material to operate in an ideal Ericsson cycle COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Spray cooling or spray chilling is a technique for obtaining solid lipid microparticles (SLMs) within the diameter range in micrometers using low temperatures and no organic solvents. It is a low-cost technique and is easy to scale-up. The production of SLMs into beta-form represents a technological challenge due to the fast crystallization given by the spray cooling system, which generally results in SLMs crystallized into the metastable polymorphic form a. This study focuses on the production and characterization of SLMs by spray cooling using hard fat soybean oil (HS) added of D-limonene or canola oil, aiming to their application as beta-seed crystals into lipid systems. The beta-seed crystals could turn into an alternative lipid material to be used in fat-based products that present the preferential beta' crystallization, like palm oil, increasing its compatibility with cocoa butter (CB) and allowing for the development of substitutes. The obtained SLMs showed spherical geometry and no agglomeration during storage at 25 degrees C for up to 30 days, verified by scanning electron microscopy (SEM). The mean diameters (D-50) were between 150 and 200 pm and the beta' and beta-form, determined by X-ray diffraction (XRD), appeared immediately after the crystallization process by spray cooling using HS added of 5% D-limonene (the HS control sample presented only the alpha-form). The SLMs of this study demonstrated their potential use as beta-seed crystals into lipid systems FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: The authors would like to thank the LNLS staff and Dr Marcus A. R. Miranda. The following funding is acknowledged: Conselho Nacional de Desenvolvimento Científico e Tecnológico (grant No. 420850/2018-0); Fundação de Amparo à Pesquisa do Estado de São Paulo (grant No. 07/08609-3) Abstract: This paper reports the successful extension of the basis of the X-ray multiple diffraction phenomenon in the assessment of structural phase transitions and the determination of thermal expansion coefficients along three crystallographic directions, using synchrotron radiation Renninger scans. Suitable simultaneous four-beam cases have accurately resolved the lattice-parameter variation in a nearly perfect single-crystal Rochelle salt using a high-stability temperature apparatus. Secondary reflections observed in the Renninger patterns, chosen by their sensitivity to the shifts in angular position as a function of temperature, have allowed the detection of a monoclinic to orthorhombic phase transition, as well as subtle expansions of all the basic lattice parameters, i.e. without having to carry out measurements on each crystal axis. The thermal expansion coefficients have been estimated from the linear fit of the temperature dependence of the lattice parameters, and are in agreement with those reported in the literature CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors would like to thank the Brazilian agencies CAPES, FAPEMA and CNPq for their partial financial support Abstract: Here, we report the results of structural, magnetic, thermal and magnetocaloric properties of ErCoSn compound. The compound undergoes an antiferromagnetic (AFM) ordering around T-N = 4.6 K and magnetic correlation is observed above T-N, up to T = 11 K. Below T-N, a spin-glass state was observed for ErCoSn due to an apparent coexistence of ferromagnetic (FM) interaction with long-range AFM order. External applied magnetic field induces a first-order-like metamagnetic phase transition from AFM to FM state that is responsible for the large values of the maximum isothermal entropy change (-Delta(max)(M) = 16.5 J/kgK@50kOe) and adiabatic temperature change (Delta T-ad = 8.2 K). Furthermore, short-range ferromagnetic correlation above T-N contributes to the widening of -Delta S-M and Delta T-ad peaks as well as the increase of the ErCoSn compound refrigerant capacity. The results indicate attractive properties of this compound for magnetic refrigeration at cryogenic temperatures FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This study was financed partly by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brazil (CAPES) - Finance Code 001, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)- Brazil (2014/21252-0) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)- Brazil (305870/2014-9, 406963/2014-4, 310272/2017-3, 309780/2014-4 and 132149/2017-6) Abstract: Fatty acids, fatty alcohol compounds and triacylglycerols (TAGs) present a significant role in industrial applications, mainly in food, cosmetics and pharmaceutical industries. In this study, eight solid-liquid phase diagrams composed by tripalmitin plus fatty acids (capric acid, lauric acid, myristic acid, palmitic acid and stearic acid) and tripalmitin plus fatty alcohol compounds (1-decanol, 1-dodecanol and 1-tetradecanol) were studied using Differential Scanning Calorimetry (DSC) technique, optical microscopy and X-ray analysis. The phase diagrams formed by tripalmitin + fatty acids (myristic acid, palmitic acid and stearic acid), present a eutectic behavior with a solid solution for tripalmitin (1) + myristic acid (4) system, and a monotectic behavior for tripalmitin + (capric acid and lauric acid) whereas the phase diagrams formed by tripalmitin + fatty alcohol compounds present a monotectic behavior and just one of them present a monotectic behavior with a solid solution (1-tetradecanol). The liquid phase was modelled using ideal assumption, 3-suffix Margules and NRTL models, adjusting its parameters. These models described properly the liquidus line of the systems studied CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Magnetocaloric properties of the intermetallic DyCo2 compound (in the form of reduced size particles) and its correlations with the itinerant electron metamagnetism (IEM) phenomenon and structural disorders are investigated and discussed. Micrometric-sized particles were prepared by a mechanical milling technique for two low milling times (4 and 8 h) and characterized by means of X-ray diffraction, scanning and high-resolution transmission electron microscopy as well as magnetic measurements as a function of an applied external magnetic field and temperature. The results show that the particles have irregular-shaped and amorphous "edges/ledges" with embedded randomly oriented DyCo2 nanocrystallites. The average particle size practically does not change with increasing milling time, whereas the average crystallite size is slightly diminished. In contrast, microstrain values that indicate lattice deformation degree were rather increased after the milling processes. Structural disorders and surface effects, features resulting from mechanical impact, disturb the Dy-Co sublattice coupling and weaken the IEM mechanism responsible for the high magnetocaloric effect found for the DyCo2 bulk sample. For the milled samples, it was observed reductions in the peak intensity of the magnetic entropy change (-Delta S-M) and substantial broadenings of the distribution profiles which have contributed to an increase of the working temperature range of the investigated magnetocaloric material CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA FINANCIADORA DE ESTUDOS E PROJETOS - FINEP Fechado

Agradecimentos: The authors gratefully acknowledge Professor Helmut Klapper from the Institute of Crystallography at RWTH Aachen, Germany, for useful discussions and for providing the X-ray topograph shown in Figure 2'. This work forms a part of the doctoral degree studies (Z.L.).27 G.A.C. thankfully acknowledges the support of CNPq, Brazil (Programa Ciencia sem Fronteiras SWE 234550/2014-7) for the support of a visiting scholarship to the EPSRC Centre for Doctoral Training in Complex Particulate Products and Processes at the University of Leeds, UK. Two of us (XL. and K.J.R) gratefully acknowledge the UK's EPSRC for their support in crystallization research at the Universities of Leeds and Manchester through their funding of the Critical Mass Project "Molecules, Clusters and Crystals" (Grant References EP/I014446/1 and EP/I013563/1, respectively). We also acknowledge the CNPq, FAPEMA, FAEPEX-UNICAMP (Brazil) for their financial support. Synchrotron beam time for the EXAFS and XRMD experiments was provided by the Diamond Light Source and the LNLS which we gratefully acknowledge Abstract: Sodium chlorate (NaClO3) crystals change from a cuboid to a tetrahedron of {(111) over bar} morphology when crystallized in the presence of sodium dithionate (Na2S2O6) impurity. Polarized extended X-ray absorption fine structure at the S K-edge, used to probe the local structure around this impurity with respect to its orientation within the bulk crystal lattice, reveals that the S-S bond of the S2O62- ions is closely aligned along the

Raman spectra of bis (L-histidinate)nickel(11) monohydrate crystal were obtained for pressures up to 9.5 GPa. Our results show the disappearance of some of the Raman modes and the appearance of other modes. These modifications evidence that the sample undergoes phase transitions at around 0.8 and 3.2 GPa. The role played by the Ni ions and hydrogen bonds in the dynamics of the phase transitions is discussed. Under decompression, down to atmospheric pressure, the original Raman spectra are recovered, showing that both phase transitions are fully reversible CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO CEARENSE DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - FUNCAP Fechado

Agradecimentos: The authors thank the Brazilian funding agencies CNPq, CAPES, FAPEMA, and FAPESP, for the financial support of this work Abstract: The characterization of fat components becomes very useful for formulation of shortening, margarines and fat products due to their unique properties of plasticity, texture, solubility, and aeration. However, X-ray diffraction experiments on such materials are usually limited to a qualitative evaluation of the polymorphic properties based only on the characteristic d-spacing peak intensities. In this work, interesting results based on the Rietveld Method have supported both a Quantitative Phase Analysis and Degree of Crystallinity study on industrial and academic appealing samples, such as triacylglycerol standards, fully hydrogenated vegetable oils (hardfats) and cocoa butter. This useful approach to the area of oils and fats can provide valuable information about the polymorphism and its relationship to the application of lipid materials in food science and technology. Here, the discrimination between beta and beta' polymorphs on samples made of mixtures or blended hardfats was attained, and the results have shown a relevant contrast in comparison to a purely qualitative approach. Assessment of amorphous content on cocoa butter samples was achieved by isolating its contribution from the total X-ray diffraction background via mathematical tools during the whole pattern fitting CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: Ariel A. C. Toledo Hijo thanks the São Paulo Research Foundation (FAPESP) (Grant # 2016/24461-5) for the scholarship and financial support. The authors thank the national funding agencies of the São Paulo Research Foundation (FAPESP) (2014/21252-0, 2016/24461-5, 2016/08566-1, 2014/03992-7, 2012/05027-1, and 2004/08517-3), the National Council for Scientific and Technological Development (CNPq) (406963/2016-9, 406918/2016-3, 406856/2013-3, 133152/2014-6, 483340/2012-0, 305870/2014-9, 309780/2014-4, and 143050/2009-5), CAPES and UNICAMP/FAEPEX (PAPDIC 0125/16) for the financial support and scholarships. J. F. B. P. acknowledges financial support by FAPESP (2014/16424-7) Abstract: Protic ionic liquid crystals (PILCs) obtained from natural sources are promising compounds due to their peculiar properties and sustainable appeal. However, obtaining PILCs with higher thermal and mechanical stabilities for product and process design is in demand and studies on such approaches using this new IL generation are still scarce. In this context, this work discloses an alternative way for tuning the physicochemical properties of ILCs by mixing PILs. New binary mixtures of PILs derived from fatty acids and 2-hydroxy ethylamines have been synthesized here and investigated through the characterization of the solid-solid-[liquid crystal]-liquid thermodynamic equilibrium and their rheological and critical micellar concentration profiles. The mixtures presented a marked nonideal melting profile with the formation of solid solutions. This work revealed an improvement of the PILCs' properties based on a significant increase in the ILC temperature domain and the obtainment of more stable mesophases at high temperatures when compared to pure PILs. In addition, mixtures of PILs also showed significant changes in their non-Newtonian and viscosity profile up to 100 s(-1), as well as mechanical stability over a wide temperature range. The enhancement of the physicochemical properties of PILs here disclosed by such an approach leads to more new possibilities of their industrial application at high temperatures FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

The negative effects of trans fatty acids and saturated fatty acids in food have been widely discussed and this has led to progressive changes in the legislation of many countries. The use of structuring agents or crystallization modifiers, as specific triacylglycerol and minor lipids have been indicated as the only viable alternative for obtaining low saturated fats with properties which are compatible with food application. In this context, phytosterols, natural products with hypocholesterolemic action, and hard fat-crystallization modulators, present a new option for structuring lipid matrices. This work characterized the effects of fully hydrogenated soybean oil and free phytosterols on the physical properties and crystallization behavior of palm oil and canola oil blends for the development of zero trans-fat bases with low levels of saturated fatty acids. The systems were evaluated for chemical composition, atherogenic index, solid fat profiles, microstructure, consistency, thermal behavior and polymorphism Resumo: Los efectos negativos de los ácidos grasos trans y los ácidos grasos saturados en los alimentos ha llevado a cambios progresivos en la legislación de muchos países. Se ha indicado que el uso de agentes estructurantes o modificadores de la cristalización, como triacilgliceroles específicos y componentes lipídicos menores, es la única alternativa viable para obtener grasas bajas saturadas que tienen propiedades compatibles con su aplicación en alimentos. En este contexto, los fitosteroles, productos naturales con acción hipocolesterolémica y moduladores de cristalización de la grasa saturada, se presentan como una reciente opción para estructurar matrices lipídicas. En este trabajo se realizó una caracterización del aceite de soja totalmente hidrogenado y fitoesteroles libres sobre las propiedades físicas y el comportamiento de cristalización de mezclas de aceite de palma/aceite de canola para el desarrollo de bases de grasas cero-trans con bajos niveles de ácidos grasos saturados. Seevaluó la composición química, el índice aterogénico, el perfil de grasa sólida, la microestructura, consistencia, y el comportamiento térmico y polimorfismo FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are grateful for the financial support received from the Brazilian Fundo de Apoio ao Ensino, a Pesquisa e a Extensao (Project PAPDIC-FAEPEX-Proc. 1413) Abstract: This work sought to obtain and evaluate zero trans-fat reduced in saturated fatty acids, with higher content of unsaturated fatty acids. Palm oil (PO) was used as the reference of zero trans lipid base. Different amounts of linseed oil (LO) were added to PO, obtaining the following blends: 100:0; 80:20; 60:40; 40:60; 20:80 and 0:100 of PO:LO (w/w%), respectively. These blends were added to fully hydrogenated soybean oil (FHSO) as the crystallization modifying agent, and to sorbitan monostearate (SMS) as the structuring element, both at a proportion of 3% to build the structured fractions. The control and the structured blends were evaluated for fatty acid composition, solid fat content, consistency, crystallization kinetics, thermal behavior, microstructure and polymorphism. With the addition of LO to the PO, an increase of up to 80% was observed in the content of alpha-linolenic acid and a reduction of saturated fatty acids to 47% in the blends. FHSO and SMS offered thermal resistance to the blends, with relevant changes in the crystallization kinetics and microstructure, affecting macroscopic characteristics with the increase in consistence. It was possible to obtain a lipid formulation with features of plasticity and enhanced nutritional quality, compatible with several food applications Fechado

Structural, magnetic and magnetocaloric properties of the ternary intermetallic compound DyMn2Si2 are studied by X-ray diffraction and magnetization measurements. It is found that DyMn2Si2 crystalizes with tetragonal ThCr2S2-type structure and exhibits four successive magnetic transitions at low temperature, around 20 K, 31 K, 38 K and 82 K, named respectively as T-1, T-2, T-3 and T-4 transitions. Large values of magnetic field (> 35 kOe) favor antiferromagnetic clusters and give rise to exchange bias effect. The different responses of T-2 and T3 to field change, induces two non-identical isothermal entropy change (-Delta S-M) peaks. The maximum values of -Delta S-M occur in temperatures around T-3 and reaches 8.2 J/kgK, for a magnetic field change of 50 kOe. Also, the presence of transitions T-2 and T-3 close to each other induces a table-like magnetocaloric effect (MCE) in a wide temperature range. Thus, the peculiar magnetic properties observed for DyMn2Si2 compound are interesting for low temperature magnetic refrigeration FINANCIADORA DE ESTUDOS E PROJETOS - FINEP FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Here, it is reported the study of the structural, magnetic properties and magnetocaloric effect (MCE) of the Eu2CuSi3 compound. Polycrystalline Eu2CuSi3 compound with AlB2-type derived hexagonal structure was successfully synthesized by arc-melting method. Magnetic measurements indicate a second-order ferromagnetic (FM) phase transition below 40 K. The effective magnetic moment of Eu is reduced compared with divalent free ion, indicating a compensation of Eu magnetic moment. Spin reorientation induce negative magnetocaloric effect below Curie temperature. The values of full width half-maximum of -Delta S-M peak (delta T-FWHM = 35 K) and maximum value of entropy change (- Delta S-M(Mix) similar to 9.5 J/kg K) for mu(0)Delta H = 6 T strongly contribute to improve the relative cooling power (RCP similar to 332 J/kg) of Eu2CuSi3 compound. As observed, delta T-FWHM value is sensibly wider than the usual values observed for first and second order magnetic phase transition compounds. Then, - Delta S-M(max) and delta T-FWHM values as well as the neglected magnetic hysteresis that were obtained for Eu2CuSi3 have shown features as a desirable second order magnetic phase transition compound for low temperature magnetic refrigeration FINANCIADORA DE ESTUDOS E PROJETOS - FINEP FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

The polar organic 2-(alpha-methylbenzylamino)-5-nitropyridine crystal (MBANP) has been studied by Raman spectroscopy at low temperatures (from 300 to 10 K). The effect of temperature change on the vibrational spectrum is discussed with the aid of DFT calculations. The behavior of the Raman spectra indicates that MBANP molecules present a different conformation at low temperatures associated with the rotation of the phenyl and pyridine rings. Temperature -dependent X-ray measurements and differential scanning calorimetry (DSC) analysis were utilized as complementary techniques to investigate the structural stability of MBANP crystal CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA FUNDAÇÃO AMAZÔNIA DE AMPARO A ESTUDOS E PESQUISAS DO PARÁ - FAPESPA Fechado

Agradecimentos: This work received financial support provided by Brazilian agencies FAPESP, FAEPEX-Unicamp, CNPq and CAPES Abstract: We report on the magnetic properties and magnetocaloric effect (MCE) for the Tb3M series, with M = Co, Rh and Ru, obtained using a heat flux technique. The specific heat of Tb3Co and Tb3Rh are very similar, with a first order type transition occurring around 6 K below the magnetic ordering temperature without any corresponding feature on the magnetization. The slightly enhanced electronic specific heat, the Debye temperature around 150 K and the presence of the magnetic specific heat well above the ordering temperature are also characteristic of many other compounds of the R3M family (R = Rare Earth). The specific heat for Tb3Ru, however, presents two peaks at 37 K and 74 K. The magnetization shows that below the first peak the system presents an antiferromagnetic behavior and is paramagnetic above 74 K. We obtained a magnetocaloric effect for M= Co and Rh, -Delta S=12 J/kg K, but for Tb3Ru it is less than 3 J/kg K (mu(0)Delta H = 5 T). We believe that the experimental results show that the MCE is directly related with the process of hybridization of the (R)5d-(M)d electrons that occurs in the R3M materials FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Aberto

Agradecimentos: The authors would like to thank to CNPq, CAPES, FAPERJ, FAPEMIG, FAPESP, and PROPPI-UFF for financial support Abstract: This paper presents the results of an investigation of the magnetic and structural properties of Mn1-xFex As compounds under hydrostatic pressure and chemical doping. The chemical doping was performed by using low Fe doping levels (x = 0, 0.003, 0.006, 0.010, 0.015, and 0.018), which emulates the negative pressure effect on the crystal structure. The results of this approach were compared with the physical pressure effect (hydrostatic pressure from 0 to 2.2 kbar) on the Mn0.997Fe0.003As. Both approaches exhibit the same magnetic behaviors: the T-C and saturation magnetization decrease as the pressure increases, for the highest pressure studied, an orthorhombic antiferromagnetic phase occurs below the critical temperature and coexists with the ferromagnetic hexagonal phase. The equivalence between hydrostatic pressure and chemical doping indicates that the Fe doping only causes structural deformation. In addition, we performed magnetic measurements at high temperature (up to 520 K) on the samples with x = 0 and 0.003 in order to investigate the magnetic behavior above T-C = 310 K. These results, along with structural characterization, clearly show that between T-C and T-t the system is a weak antiferromagnet with short-range order confined only in the ab plane. Finally, using the low- and high-temperature data, the magnetic phase diagrams of the compound under hydrostatic pressure and chemical doping were redrawn CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: The authors would like to thank the financial support of the Brazilian agencies CNPq, FAPESP, FAPEMA, the LNLS (XRD2 beamline) staff and Sérgio Morelhão for useful discussions Abstract: In this paper, the dependence of a Laue diffraction streak on the crystalline perfection of Xe-implanted Si(001) substrates is presented, based on the observation in the X-ray multiple diffraction (XRMD) mappings, as an experimental evidence of the transition between dynamical and kinematical diffraction regimes. A direct observation of the implanted region by transmission electron microscopy revealed an amorphous Si layer, which recrystallizes into a heavily twinned and faulted microstructure after thermal treatment at 800 degrees C. Besides the lattice damages, the annealing induces the formation of Xe bubbles. Both singularly affect the XRMD pattern, primarily the fourfold streaks profile of the (000)(002)(1 (1) over bar(1) over bar)(1 (1) over bar3) four-beam simultaneous case when compared with the pristine Si pattern, highlighting the intra-and inter-block diffractions and the role played by the primary extinction effect. Such features provide information on the dominant diffraction regime. The findings are also discussed and compared to the conventional reciprocal space mappings via the asymmetric Si(113) reflection CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA Fechado

Agradecimentos: The authors acknowledge Fondazione Cariparma, Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP(03/12604-6), FAPES, and CNPq for financial support. This work was also part of an Industrial Partnership Programme IPP I28 of the "Stichting voor Fundamenteel Onderzoek der Materie (FOM)" which was financially supported by the "Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)" and co-financed by BASF New Business Abstract: We present direct measurements of the magnetocaloric effect on a Fe2P-based compound induced by a milliseconds pulsed magnetic field of 1 T to test their possible use in high frequency (up to 100 Hz) thermomagnetic cycles. The reported measurements were performed with an innovative and versatile non-contact set up based on the mirage effect. The adiabatic temperature change of a MnFeP0.45As0.55 sample is presented and compared with measurements performed varying the same magnetic field in a time interval of 1 s and 100 ms. These results demonstrate the absence of kinetic constraints in the first-order phase transition of this sample induced on the milliseconds time scale. The study of the materials' response to millisecond magnetic field pulses represents a fundamental test for the development of more powerful and efficient magnetic refrigerators FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA E INOVAÇÃO DO ESPÍRITO SANTO - FAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: The authors wish to acknowledge the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP – Proc. 2009/53006-0) for the financial support Abstract: The essential oils obtained from citric fruits have been used as aromatizing agents in various foods.However, the addition of orange essential oil,D-limonene, to cocoa butter (CB) has been shown to havean in?uence on its crystallization behavior. The objective of this study was to evaluate the in?uence ofaddingD-limonene at concentrations of 1.5 and 5% w/w on the polymorphic transitions in Brazilian CBand in a commercial cocoa butter equivalent (CBE). X-ray diffraction (XRD) was used to identify thepolymorphic forms in the samples over 27 days of storage at 25°C. The results showed thatD-limoneneaddition was able to accelerate the polymorphic transition in CB and CBE. The addition of 5% w/wD-limonene to Brazilian CB accelerated the complete transition from bV to the more stable bVIpolymorphic form in only 11 days. Under the same conditions, pure CB remained in bV form and thetransition was not completed in CBE samples. The polymorphic transition of CBE samples appeared tobe governed by the characteristics of the triacylglycerol (TAG) pro?le and only intensi?ed withD-limonene incorporation FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: F.F. Sousa, Ph.D, acknowledges the support from MCT/CNPq Edital (Grants #: 484592/2013-0; 311942/2013-0; 482495/2011-1). G.D. Saraiva, Ph.D, also acknowledges the support from the MCTI/CNPQ/Universal 14/2014 (Grants #449471/2014-4) and the PQ – 2014 (Grants #306631/2014-8). The authors also wish to thank the following Brazilian institutions CAPES, FAPESPA, FUNCAP and FAPEMA. We further acknowledge the professor A.G. Souza Filho for the critical reading of this work Abstract: This paper reports the temperature-dependent measurements in the C form of stearic acid. Raman scattering, X-ray diffraction, and differential scanning calorimetry measurements were performed at low temperatures. The polarized Raman spectra were measured for temperatures ranging from 8 to 300 K over the spectral range of 30-3000 cm(-1). The spectral changes observed in both the lattice vibrational modes and the internal vibrational modes regions of the Raman spectrum, allowed to identify a phase transition undergone by the stearic acid crystal occurring between 210 and 170 K and a change in the structure continues to be observed down to 8 K. The anharmonicity of some vibrational modes and the possible space groups presented by the crystal at low temperatures were also discussed. Low-temperature X-ray diffraction measurements were performed from 290 to 80 K and the results showed slight changes in the lattice parameters at similar to 200 K. Furthermore, the evidence of the phase transformation was provided by the differential scanning calorimetry measurements, which identified an enthalpic anomaly at about 160 K CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO AMAZÔNIA DE AMPARO A ESTUDOS E PESQUISAS DO PARÁ - FAPESPA FUNDAÇÃO CEARENSE DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - FUNCAP FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA Fechado

Sugar and alcohol industries generate large amount of wastes that could produce ashes of great reactivity with pozzolan properties. The objective of this paper is to evaluate the pozzolanicity of Sugar Cane Straw Ashes (SCSA), thermal treated, at different curing times. Employing Synchrotron X-ray radiation for XRD measurements, scans from 10 degrees to 110 degrees (theta - 2 theta setup) allowed the quantification of several phases of the cement pasts through Rietveld analysis. The SCSA substitution of 20% (weight) in Ordinary Portland Cement (OPC) has improved the AFt (Ettringite) formation up to 47% for 90 days curing time. The Portlandite concentration analysis allowed concluding that this addition of SCSA in OPC has caused a delay in the cement setting time. Moreover, the behaviour of the C3S and Calcite contents in both OPC and OPC/SCSA samples were determined by refinement of the XRD pattern using the Rietveld method Fechado

Agradecimentos: This material is based upon work supported by CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo, and FAPEMIG, Fundação de Amparo à Pesquisa do Estado de Minas Gerais Abstract: An overview of the magnetocaloric properties of the MnAs1-xSbxis presented. The temperature dependence of the isothermal magnetic entropy, ?Smag, and the refrigerant capacity, RC, have been investigated theoretically and experimentally in a composite based on second order MnAs1-xSbxphases. This work demonstrates the outstanding agreement between the experimental results and the continuous curves predicted by numerical calculations, indicating that this approach can be used to design magnetic refrigerant materials with enhanced magnetocaloric response in magnetic refrigerator performing an Ericsson cycle near room temperature CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG Fechado

Agradecimentos: JCGT greatly thanks Dimitri Argyriou (ESS, Sweden), Walter Kalceff (University of Technology, Australia), and Vinícius S. R. de Sousa (UERJ, Brazil) for providing fruitful discussions. The research of JCGT at the NBI was supported by the Brazilian Science Without Borders program (funds from CNPq), and further support was also provided by the Brazilian agencies FAPESP, Capes, and CNPq. The work performed at the large-scale facilities by JCGT, NCB and HNB was financed by Danscatt, while measurements performed on E9 (JCGT and HNB) and on TOFTOF (JCGT and NBC) were supported by the European Commission under the 7th Framework Programme through the ‘Research Infrastructures’ action of the ‘Capacities’ Programme, NMI3-II Grant number 283883. The authors gratefully acknowledge ISIS for the provision of beam time Abstract: Neutron powder diffraction and inelastic neutron scattering data were used to simulate and understand the magnetization and heat capacity curves of the pseudobinary TbxPr1-xAl2, with x = 0.10 and 0.25, as a function of temperature. From the Rietveld analysis, we concluded that no crystallographic transition occurs in these samples, and the high symmetry of the magnetic structure was confirmed. Moreover, the different contributions from the reflection planes could be related to the known exchange bias-like effect characteristic for the x = 0.25 sample, also suggesting the existence of some rearrangement of the magnetic moments or even the presence of spin frustration in this system. Finally, the obtained set of theoretical parameters using the mean field approach for the two systems consisting of two sublattices allowed the experimental data to be described and to explain their physical behaviors. The ensemble of our results leads us to affirm that the quadrupolar interactions as well as an existence of some rearrangement of the magnetic moments or a frustration play an important role in the strong unidirectional anisotropy and the exchange bias-like effect observed in this pseudobinary system CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Fatty alcohols and fatty acids are used in the cosmetic, pharmaceutical and food industries as surfactants. They are also considered phase change materials for thermal storage processes. Information on their thermal properties is required for optimizing production processes as well as for improving their industrial and home use. In the present study, the solid-liquid phase diagrams of three binary systems of 1-tetradecanol + dodecanoic acid, 1-hexadecanol + tetradecanoic acid and 1-octadecanol + hexadecanoic acid were determined by differential scanning calorimetry. The phase-transition phenomena were further investigated by optical micrographs and X-ray diffraction patterns. The experimental data showed that the systems present eutectic transitions and some of them exhibit partial solid phase miscibility. The liquid phase activity coefficients were calculated by Margules 2 and 3-suffix and by UNIFAC and UNIFAC-Dortmund methods. The modeling approach resulted in an accurate prediction, with average absolute deviations from experimental data lower than 1.16 K. The values of excess Gibbs free energy present an unusual behavior, with positive deviations at very low alcohol concentrations and negative ones at high concentrations of this component. This occurs due to changes in the H-bonding interactions along the concentration range of the mixture FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

In this work, differential scanning calorimetry and X-ray diffraction techniques were employed to evaluate the influence of the winterization process on the low temperature properties of methyl babassu biodiesel. The results have shown that the crystallization onset temperature for the non-winterized biodiesel is around 266.4 K (-6.6 A degrees C) which is reduced to 263.6 K (-9.4 A degrees C) for the liquid fraction of winterized biodiesel. The 14 % reduction in the amount of saturated fatty acid methyl esters is probably responsible for the improvement of low temperature properties of winterized methyl babassu biodiesel FINANCIADORA DE ESTUDOS E PROJETOS - FINEP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA Fechado

Agradecimentos: The authors are grateful to CNPq (483340/2012-0, 304495/2010-7, 552280/2010-0, 142193/2010-0, 479533/2013-0), FAPESP (2007/06162-1, 2008/09502-0, 2008/56258-8 and 2012/05027-1), CAPES and FAEPEX/UNICAMP for their financial support and assistantships Abstract: The solid-liquid phase diagrams of the following binary mixtures of even saturated fatty alcohols are reported in the literature for the first time: 1-octanol (C8OH) + 1-decanol (C10OH), 1-decanol + 1-dodecanol (C12OH), 1-dodecanol + 1-hexadecanol (C16OH) and 1-tetradecanol (C14OH) + 1-octadecanol (C18OH). The phase diagrams were obtained by differential scanning calorimetry (DSC) using a linear heating rate of 1 K min-1 and further investigated by using a stepscan DSC method. X-ray diffraction (XRD) and polarized light microscopy were also used to complement the characterization of the phase diagrams which have shown a complex global behavior, presenting not only peritectic and eutectic reactions, but also the metatectic reaction and partial immiscibility on solid state CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: We thank Vinicius R. S. Souza for fruitful discussions. We also thank FAPESP, FAPEMA and CNPq, Brazilian agencies, for financial support Abstract: In this work we study the anisotropic magnetocaloric properties of ErGa2 and HoGa2 single-crystals. Both compounds present antiferromagnetic ordering below 10 K but with different easy axis as a result of the crystal field anisotropy. The single-crystal conventional MCE values are similar or in certain circumstances even larger than the results for the polycrystalline material. The anisotropic MCE was calculated by taking the difference of the entropy change of the easy and hard magnetization directions. For both compounds, the anisotropic variation of entropy is as large as the conventional entropy change obtained by sweeping the magnetic field up to 5 T. Particularly for ErGa2 an inverse MCE for a 3 T field oriented along the easy axis is obtained with similar magnitude of the 5 T MCE found for polycrystalline samples. The results show that by exploring anisotropic properties of the materials it is possible to obtain a significant MCE. From a technological point of view this can be an interesting alternative because the MCE is produced just by rotating the magnetic material under a constant magnetic field FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: The authors gratefully acknowledge the generous support of the Brazilian research funding agencies, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), and Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) Abstract: Enzymatic interesterification has been shown to be an alternative for the production of structured lipids resembling human milk fat. The knowledge of the physical properties of fat is an important tool for the implementation of this fat in a food matrix. The enzymatic interesterification reaction modifies the composition of triacylglycerols changing the crystallization properties and polymorphic form of fats. Blends containing different proportions of lard and soybean oil (80:20, 70:30, 40:60, 30:70 and 20:80) were enzymatically interesterified in a continuous flow tubular reactor and analyzed for crystalline structure by polarized light microscopy, the polymorphic form using X-ray diffraction and thermal properties by differential scanning calorimetry. The structural modifications resulting from continuous enzymatic interesterification changed the crystallization behavior and thermal profile of the samples, reducing enthalpy values. Structural changes were also evident on polarized light microscopy images, disclosing an increase in the crystallization rate among the samples after the continuous enzymatic reaction CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are grateful for access to the facilities of Laboratorio Nacional de Luz Sincrotron (LME-LNLS) on proposal HRTEM-7362. This work was supported by Brazilian agency CNPq and also by FAPITEC (Sergipe) Abstract: Ce1-xFexO2 nanocrystals (0 < x < 0.05) have been synthesized at room temperature using the coprecipitation method. The samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and magnetization measurements as a function of field. The XRD results and Rietveld refinement analysis show that all particles have a crystalline structure isomorphous to the host structure (CeO2), with average size of 9 nm. This information was also confirmed by TEM images in which it is shown that the particles present spherical-like shape. The magnetic measurements indicated that the Fe-doped samples exhibit a weak ferromagnetism at room temperature, which increases with the increasing of the Fe content CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE APOIO À PESQUISA E À INOVAÇÃO TECNOLÓGICA DO ESTADO DE SERGIPE - FAPITEC Aberto

Agradecimentos: The authors would like to acknowledge Flavio Garcia from Brazilian Synchrotron Light Laboratory for useful discussions and ideas, and the Brazilian Agencies CAPES, CNPq, FAPESP and FAPERJ for financial support Abstract: The magnetic behavior of pseudobinary Pr0.7Tb0.3Al2 and Pr0.75Tb0.25Al2 compounds was studied, and a predominant ferrimagnetic ordering was observed. Noteworthy characteristics such as negative magnetization, compensation points and exchange-bias-like (EB-like) effect were found. This EB-like effect was observed at temperatures below the compensation points. The effect is somewhat different from the one already studied in similar systems combining light and heavy rare earths. The results indicate that the EB-like effect characteristics are related to the conduction electron magnetic polarization and an induced unidirectional anisotropy present in these compounds COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJ Aberto

Agradecimentos: Authors would like to acknowledge the financial support from the Brazilian agencies FUNCAP, FAPEMA and CNPq. We also thank the CENAPAD-SP for the use of the GAUSSIAN software package and the computational facilities through the project reference proj373 Abstract: In this work the Fourier transform infrared and the Raman spectra of bis(L-hisidinato)nickel(II) monohydrate were recorded at room temperature. Optimized geometry and vibrational frequencies were obtained by means of Density Functional Theory (DFT). Experimental and theoretical vibrational spectra were compared and a complete analysis of the modes was done in terms of the Potential Energy Distribution (PED) FUNDAÇÃO CEARENSE DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - FUNCAP FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMA CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: The authors acknowledge funding by FAPESP, CAPES and CNPq. The cooperation of Dr. Stanislav A. Moshkalev and Dr. Alfredo Vaz, from the Center for Semiconductor Devices - UNICAMP, for the SEM images, is also greatly acknowledged Abstract: Investigations of magnetic phases, transition temperatures and coercivity were performed inmultilayered Gd/Cr films as a function of the crystalline state and morphology of the Gd layers. The films were deposited by dc magnetron sputtering at three substrate temperatures, T-s, (room temperature, 300 and 500 degrees C). The Gd and Cr thicknesses were of 10 and 30 nm, respectively. Two series of three films were prepared. In one of the series, the films had a single Gd/Cr bilayer; in the other, 15 bilayers. The discontinuous or granular nature of the Gd layers was revealed by scanning electron microscopy Grazing incidence angle x-ray diffraction was used to investigate the crystalline state of the Gd and Cr layers. These techniques revealed that grain average size and crystalline order increase with increasing T-s. From dc magnetic measurements, the co-existence of ferromagnetic and superferromagnetic phases in the Gd layers was observed, and Curie transition temperatures, T-C, were determined. High coercive fields at low temperature (2 K) were measured in hysteresis cycles. Field-cooled and zero field-cooled magnetizations as functions of temperature curves exhibited, for some of the samples, a low temperature peak suggesting a freezing transition to a cluster glass state. This was confirmed by complementary ac-susceptibility measurements carried out as a function of temperature, for various frequencies of the ac field. Some results of this work - the decline in TC for decreasing Gd grain size, the high coercive field and its dependence on particle size, and the behavior of the magnetization at low temperatures for the sample deposited at room temperature - are discussed in terms of finite size and surface effects in nanosized particles FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: To the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP - Proc. 2009/53006-0 and Proc. 2010/18504 -7) for the financial support Abstract: The microstructural behavior of industrial standardized cocoa butter samples and cocoa butter samples from three different Brazilian states is compared. The cocoa butters were characterized by their microstructural patterns, crystallization kinetics and polymorphic habits. The evaluation of these parameters aided in establishing relationships between the chemical compositions and crystallization behavior of the samples, as well as differentiating them in terms of technological and industrial potential for use in tropical regions Resumen: En este trabajo se presenta el comportamiento de la microestructura y la cristalización de mantecas de cacao representativas de las mezclas industriales, y de la manteca de cacao original de tres regiones geográficas diferentes de Brasil. Las muestras se evaluaron de acuerdo a la microestructura, la cinética de cristalización y el comportamiento polimórfico. La evaluación de estos parámetros nos permite establecer relaciones entre la composición química y el comportamiento de la cristalización de las muestras, así como las diferencias sobre la adecuación del potencial tecnológico e industrial para su aplicación en las regiones tropicales FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: This work was financially supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)/Brasil, Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB)/Brasil, and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)/Brasil. We are indebted to Professor Myriam P. Sarachik for valuable discussions and help during the course of this project Abstract: The structural, optical and electrical properties of InN polycrystalline films on glass substrate are investigated by means of X-ray photoelectron spectroscopy, Raman scattering measurements, X-ray diffraction analysis, optical spectroscopy, and electrical measurements as a function of the inverse of temperature. The absorption edge for the films is most likely due to an impurity band formed by the presence of defects in the material. Such an impurity band, located at 1.6 eV extends itself to about 1.8 eV above the Fermi level, and it is attributed to nitrogen vacancies present in the material. The Raman scattering data also reveal the incorporation of oxygen in the InN films, leading to the formation of the In2O3 amorphous phase during the process of sputtering. Additionally, the X-ray photoelectron spectroscopy of the valence band, which is highly desirable to the determination of the Fermi level, confirms the optical gap energy. Furthermore, the X-ray diffraction patterns of the thinner films present broader peaks, indicating high values for the strain between the film lattice and the glass substrate. Finally, first principles calculations are used to investigate the optical properties of InN and also to support the experimental findings CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DA BAHIA - FAPESB FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

The structure and ferroelectric properties of PbZr0.53Ti0.47O3 thin films were investigated in detail by using the x-ray diffraction technique. The surface morphology of the film was studied by using the atomic force microscopy technique, showing a film with a dense morphology and a smooth surface. Based on recent results reported by Pandey et al (2008 Acta Crystallogr. A 64 192), Rietveld refinements of the structure were conducted considering different models proposed in the literature. Results suggested the monoclinic and tetragonal (M + T) phase coexistence, with P4mm and Cm space groups, respectively. The monoclinic phase (68 mol%) is dominant over the tetragonal phase (32 mol%) for this PZT film composition FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Magnetic refrigeration is a good alternative to gas compression technology due to higher efficiency and environmental concerns. Magnetocaloric materials must exhibit large adiabatic temperature variations and a large entropic effect. MnAs shows the colossal magnetocaloric effect under high pressures or with Fe doping. In this work the authors introduce a class of materials-Mn1-xCuxAs-revealing a peak colossal effect of -175 J/(K kg) for a 5 T field variation at 318 K and ambient pressure FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

The effect of hydrogen absorption (

Agradecimentos: This work was accomplished under contract, project title FILIMON35 no. ANR-05-NANO-016-03 France, and Brazilian Agencies: Capes, CNPq and Fapesp (proc. N. 05/55861-4) Brazil Abstract: This paper presents the growth and characterization of three-dimensional structures using metal-organic (or organometallic) chemical precursors like M(CH3)(3), where M is a metal. Their morphology depends principally on growth temperature and conditions at the surface of the substrate. These 3D structures can be separated into two classes: i) one with (Ga, Al, In) metallic alloys shaped as sphere, sceptre or cylinder and a carbon membrane covering the alloy; ii) the other with semiconductor or oxide nanowires capped by a metallic sphere. The metal-organic precursors can be seen as catalysts molecules that grow semiconductors with micro and nanostructures similar to the role of gold particles used to grow nanowires in the VLS mechanism. We present the MOCVD growth of Ga2O3, CuGaxOy and (Ga,ln)P nanowires using the metal-organic precursors on metallic or metal containing substrates COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors thank the Brazilian Agencies CNPq, CAPES and are grateful for support from the Laboratório Nacional de Luz Síncrotron (LNLS), Campinas, SP, Brazil Abstract: The method for determining piezoelectric coefficients based on synchrotron radiation x- ray multiple diffraction ( Avanci et al 1998 Phys. Rev. Lett. 81 5426) has been used in the case of a single crystal of the amino acid L- histidine center dot HCl center dot H(2)O. The method relates the E- induced strain with the angular shift in the multiple diffraction peak position. Thus, it allowed us to determine all three (d(14) = 2.25( 9) x 10(-10) C N(-1), d(25) = 4.1( 5) x 10(-11) C N(-1) and d(36) = 2.3(2) x 10(-10) C N(-1)) piezoelectric coefficients of L- histidine center dot HCl center dot H(2)O, using the ( 10 0 0) and ( 0 0 4) primary reflections CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

We report a study about the structural properties of polycrystalline samples of nominal composition Gd5Ge2(Si1-xSnx)(2) (x = 0.23, 0.40) that closely influence their physical behavior particularly related to electric resistivity and magnetocaloric (MCE) effect. The samples were characterized by X-ray diffraction (XRD) using the Rietveld refinement method, metallographic analyses, Sn-119 Mossbauer spectroscopy, DC magnetization and electrical transport measurements. It was identifieda Gd5Si2Ge2-monoclinic phase for x = 0.23 and a Sm5Sn4-orthorhombic phase (type II) for x = 0.40, both with two non-equivalent crystallographic sites for the Sn ions. We were able to infer on the role of tin on the magnetic and transport properties in these compounds COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Orientadores: Lisandro Pavie Cardoso, Marco Sacilotti Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin Resumo: Os nitretos (Ga, Al, In)N assim como os compostos GaInP, GaCuO2, representam um sistema de materiais muito importante para as aplicações em opto-eletrônica e dispositivos tais como os diodos emissores de luz (LEDs), lasers e nanosensores. Entretanto, o requisito essencial para as aplicações industriais desses materiais é a redução em seus tamanhos. Neste trabalho foram crescidos materiais metálicos formados por nitretos de gálio e também de semicondutores do tipo GaInP, GaCuO2 na forma de estruturas 3D, pela técnica de deposição química de organometálicos em fase vapor (MOCVD). Foi utilizado como precursor organometálico (OM) o trimetil gálio Ga(CH3)3e o nitrogênio N2 como gás portador. A temperatura e a pressão foram controladas durante o crescimento variando entre 500 e 750 o C e 100 a 760 Torr, respectivamente. Duas classes de estruturas 3D foram obtidas a partir da decomposição total ou parcial do gás pre-cursor, devido a interação entre o OM e o substrato que gera diferentes morfologias: i) as ligas metálicas (Ga, Al, In) formando estruturas semelhantes a balões, cetros (hastes com terminações esféricas) e neurônios, todos apresentando uma fina membrana de carbono amorfo que reveste a estrutura. Após o crescimento, estas estruturas foram submetidas ao processo de nitretação sob atmosfera de NH3 para transformá-las em micro/nanocristais de GaN; ii) os fios semicondutores micro/nanométricos com uma esfera metálica em sua terminação (bambus e cetros). Na formação de ambas as estruturas, os precursores OM são como moléculas catalisadoras do crescimento. Este crescimento é considerado como um método alternativo e original para se obter estruturas 3D. Uma possível associação com o modelo apresentado pelo mecanismo de crescimento Vapor-Líquido-Sólido (VLS), que utiliza uma partícula metálica para promover os nanotubos de carbono e os nanofios semicondutores, ainda está em discussão. Informações estruturais e ópticas dessas novas estruturas crescidas sobre substratos de Cu (grade de difração), Si (001), InP (policristalino) e Al/SiO2/Si (fotolitografia) foram obtidas através da caracterização por difração de raios-X, microscopia eletrônica de varredura e de transmissão em alta resolução, espectroscopia por energia disper-siva, catodoluminescência e a espectroscopia de excitação por dois fótons. Nas amostras nitretadas, micro/nano cristais de GaN obtidos da liga de Ga aparecem impregnados no carbono turbostrático (folhas de carbono sem orientação obtidas do amorfo) que revestem as estruturas, e emitem na região do espectro l £ 365 nm, devido às suas dimensões quânticas. As hastes das estruturas do tipo bambus apresentam nódulos formados por discos monocristalinos de GaInP rotacionados de 60 o um em relação ao outro. Óxidos CuGaO2 e CuGa2O4compondo nanofios, denominados cetros, também foram obtidos Abstract: Nitride (Ga, Al, In)N as well as GaInP, GaCu O2 compounds represent a very important class of materials to be used in the opto-electronic and devices applications such as light emission diodes (LEDs) lasers and nanosensors. However, the essential requirement to the industrial applications of these materials is the reduction in theirs sizes. In this work 3D structures based on gallium nitride and also GaInP, GaCuO2 semiconductors were grown by metalorganic chemical vapor deposition (MOCVD) technique. Trimethyl-gallium Ga(CH3) was used as the metal-organic (MO) precursor and nitrogen N2as carrier gas. During the growth to the temperature and pressure intervals of 500 - 700 oC and 100 - 760 Torr, respectively. Two 3D material classes were obtained from the total or partial precursor gas decomposition, since the interaction between the MO compound and the substrate gives rise to different morphologies: i) (Ga,In,Al) metallic alloys form ballons, scepters (wires with spherical ends) and neurons like structures, all involved by a thin carbon amorphous membrane. After growth, these structures were turned into GaN micro/nanocrystals by nitridation process under NH3 atmosphere; ii) micro/nanometer semiconductor wires with a metallic sphere at its end (bamboos and scepters). In order to form both structures, the MO precursors are taken as a catalyst molecule of the growth process. This is an alternative and original method to obtain 3D structures and a possible association to the model used in the vapour-liquid-solid (VLS) growth mechanism, in which a metallic particle promotes the carbon nanotubes and semiconductors nanowires is still under discussion. Structural and optical informations on these new structures grown on Cu (diffraction grid), Si(001), InP (polycrystalline) and Si/Al (photolithography) substrates were obtained through the characterization by X-ray diffraction, scanning electron microscope, high resolution transmission electron microscopy, en-ergy dispersive x-rays, cathodoluminescence and two photon excitation. In the nitrided samples, GaN micro/nanocrystals obtained from Ga alloy appear embedded in the turbostratic carbon (C sheets at random obtained from the amorphous) which involves the structures and, they emit in the l £ 365 nm region specter, due to their quantum dimensions. The bamboo rods present nodes consisting of GaInP single crystal discs turned by 60o one with respect to the other. The CuGaO2 and CuGa2O4 oxides compounding nanowires, called scepters, also were obtained Doutorado Física Doutor em Ciências

Orientador: Lisandro Pavie Cardoso Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin Resumo: Neste trabalho, estruturas heteroepitaxiais semicondutoras foram estudadas através de diagramas Renninger obtidos com radiação de freamento de elétrons e radiação síncroton. Na simulação dos diagramas Renninger, o programa MULTX, que usa o método iterativo para o cálculo de intensidades em difração múltipla de raios-X foi implementado de forma a permitir a sua utilização. O fator de polarização para a radiação síncroton e o caminho médio dos feixes difratados dentro do cristal foram implementados no programa. Montagens experimentais automatizadas de alta resolução foram desenvolvidas para a caracterização das amostras e obtenção de diagramas Renninger com radiação de freamento de elétrons. O estudo dos diagramas Renninger com esta radiação mostrou quebra de simetria nas intensidades para a direção [111] em cristais cúbicos, que foram simuladas pelo MULTX. Também mostrou que as intensidades do diagrama Renninger são sensíveis à composição de AI em amostras GaAIAs/GaAs, sendo o caso de 4-feixes (000 002 113 111) Bragg-Laue o mais sensível para amostras espessas (t > 3mm) e o caso de 3-feixes de superfície (000 002 111) para amostras finas (t < 3mm). Reflexões híbridas, observadas pela primeira vez em diagramas Renninger para amostras GaAs/Si, mostraram a viabilidade de sua utilização na caracterização de estruturas heteroepitaxiais, e foram aplicadas ao sistema InGaAsP/GaAs. Com relação ao estudo do diagrama Renninger com radiação síncroton, o diagrama experimental para o lnP 006 foi utilizado como padrão para os testes da polarização e do caminho médio dos feixes difratados. Diagramas Renninger obtidos para amostra lnGaAs/ AlGalnAs/InP foram simulados com o programa MULTX, e entre outros efeitos, a simulação evidenciou o desdobramento do caso de 6-feixes em X = 90°, devido à deformação tetragonal na rede da camada Abstract: In this work, Renninger scans obtained with Bremsstrahlung and synchrotron radiation were used to study semiconductor heteroepitaxial structures. The program MULTX was implemented to provide Renninger scan simulations and it is based on the iterative method to calculate X-ray multiple diffraction intensities. The polarization factor for the synchrotron radiation and also the diffracted beam path length were considered into the MULTX program. In order to characterize the sample to be analyzed and perform Bremsstrahlung Renninger scans automatized experimental setups with high resolution were developed. The study of these Renninger scans has shown symmetry loss in the multiple diffraction intensities for the [111] direction in cubic crystals, which were simulated by MULTX. It has also shown that the intensities are sensitive to the AI composition in GaAlAs samples, being the 4-beam Bragg-Laue case (000 002 113 111) the most sensitive for thick samples (t > 3mm) whereas the 3- beam surface case (000 002 111) is the best choice for thin samples (t < 3mm). Hybrid reflection which were observed by the first time in GaAs/Si Renninger scans have shown the feasibility of its use in the characterization of heteroepitaxial structures. As an application the InGaAsP/GaAs system was characterized. Regarding the study of synchrotron radiation Renninger scan the experimental InP 006 scan was taken as a standard to check the polarization factor and the diffracted beam pad1Iength. InGaAs/AlGaInAs/InP samples were analyzed and experimental Renninger scans were simulated with the MULTX program. The split of the 6-beam at X = 90° due to the layer tetragonal distortion, among other effects, was simulated. Doutorado Física Doutor em Ciências

Orientador: Lisandro Pavie Cardoso Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin Resumo: Neste trabalho, o potencial da técnica de difração múltipla (DM) de raios-X, para o estudo de heteroestruturas e substratos semicondutores, é explorado. A DM de três feixes (incidente, primário e secundário), com o feixe secundário paralelo à superfície, é a principal ferramenta para esta exploração. Nos heterosistemas com apenas uma camada depositada sobre o substrato, utiliza-se a ocorrência de dois tipos diferentes de reflexões híbridas, com as seqüências de espalhamento substrato-camada (SL) e camada-substrato (LS), para se desenvolver novos métodos de caracterização dos sistemas. A teoria de DM em cristais mosaicos é estendida, para levar em conta também a ocorrência de reflexões híbridas. Foi desenvolvido um programa que simula, amenos da intensidade, a posição e o perfil dos picos de DM esperados e os híbridos, e fornece informações sobre: a perfeição cristalina (largura mosaico) das redes camada e do substrato, a inclinação e a rotação relativa entre essas redes, e sobre a discordância de parâmetros de rede na direção paralela (ou densidade de deslocações) à interface. Amostras de GaAs/Si(001) com camadas de diferentes espessuras são analisadas. As reflexões híbridas SL são empregadas na análise das amostras com camadas espessas (600 a 2800nm), e as LS, na amostra com apenas uma fina camada (pré-camada de 5Onm). Da medida da híbrida LS mostra-se, que a densidade de deslocações e o estado de tensão (tração ou compressão) na camada fina e na espessa são diferentes. A adesão nas interfaces camada/pré-camada e pré-camada/substrato, também é investigada a partir das medidas de DM híbrida. A perfeição cristalina na superfície de semicondutores, em função do seu tratamento, é analisada a partir de um novo método, baseado no mapeamento bidimensional do perfil do pico DM. Na interpretação dos resultados, propõe-se um modelo de cristal quase perfeito, entre o idealmente imperfeito e o altamente perfeito, e observa-se que, o polimento químico-mecânico aplicado no acabamento da superfície de substratos de GaAs(001), aumenta a largura mosaico no plano da superfície. Para amostras de Ge(001), o método mostra, que após o polimento mecânico da superfície, o perfil do pico é semelhante ao simulado com modelo de cristal ideal mente imperfeito. Após polimento químico, o perfil obtido, só é explicado a partir do modelo de cristal quase perfeito Abstract: In this work. the potential of the X-Ray Multiple Diffraction (MD) technique in studying the heterostructures and semiconductor substrates is investigated. The three-beam (incident, primary and secondary) MD with the secondary parallel to the surface. is the main tool for this investigation. The occurrence of the two types of hybrid reflections in heterostructures. involving the scattering sequences substrate-layer (SL) and layer-substrate (LS). is used to develop a new method of characterizing these structures. The MD theory in mosaic crystals is extended in order to take into account the hybrid reflections occurrence. A computer program to simulate the position and profile of the expected and hybrid MD peaks was developed and it provides informations on: the crystalline perfection (mosaic spread) of the layer and substrate lattices. the tilt and relative misorientation between these lattices and. on the lattice mismatch in the direction parallel (dislocation density) to the interface. GaAs/Si(001) samples with several thicknesses were analyzed. The SL hybrid reflections are used in the analysis of the thick layer samples (600 to 2800 nm) while the LS ones are used just to analyze thin buffer layers (50 nm). Different dislocation densities and stress states (tensile or compressive) in thin and thick layers can be obtained from the LS measurements. The adhesion in the interfaces layer/buffer and buffer/substrate is also investigated from the MD hybrid measurements. A new method based on the two-dimensional mapping of the MD peak profile was developed to assess the crystalline perfection on the semiconductor surface as a function of its finishing. A proposed quasi-perfect crystal model. between the ideally imperfect and the highly perfect crystal, appears in the light of the results. The method allows to observe that the mechanic-chemical polishing applied to the GaAs(001) substrate surface finishing increases the sample mosaic spread in the surface plane. It also shows that for mechanic polished Ge(001) samples. the peak profile is similar to the one simulated with the ideally imperfect crystal model. After the chemical polishing the quasi-perfect crystal model has to be used in order to explain the obtained profile Doutorado Física Doutor em Ciências

Orientador: Lisandro Pavie Cardoso Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin Resumo:Neste trabalho, heteroestruturas semicondutoras com camadas finas de espessura variável de GaxIn1-xP, crescidas sobre substratos de GaAs(001) através da técnica de Epitaxia por Feixe Químico (CBE), foram analisadas por curvas de rocking e difração múltipla de raios-X. Através das curvas de rocking em sistemas de duplo-cristal e também triplo-eixo, foi possível determinar a estrutura analisada com as composições, os parâmetros de rede perpendiculares e as espessuras das camadas que compõem cada uma das amostras. Camadas buffer de GaAs tensionadas e a presença de camadas interfaciais finas (13 a 20 Þ ) de GaAsyP1-y entre as camadas GaxIn1-xP e buffer, foram obtidas das simulações das curvas de rocking, realizadas com programa baseado na teoria dinâmica de raios-X, fornecendo assim, os melhores ajustes para as curvas experimentais. A técnica de difração múltipla de raios-X mostrou-se de extrema utilidade neste trabalho, pois as varreduras Renninger, em torno dos picos BSD, caso especial da difração múltipla em que o feixe secundário se propaga paralelamente à superfície da amostra, mostraram sensibilidade suficiente para a detecção dos picos híbridos que correspondem as contribuições de diferentes redes em uma única varredura. O ajuste desses picos com o programa baseado na difração múltipla[19] , permitiu a determinação dos parâmetros de rede paralelos às interfaces e a largura mosaico das camadas GaxIn1-xP, e de camadas interfaciais de GaAsyP1-y, que já haviam sido detectadas por curvas de rocking. Foram ainda obtidas topografias de superfície em todas as amostras, através de microscopia de força atômica, e o comportamento das curvas rugosidade média versus espessura foi relacionado à tensão na rede, provavelmente causada pela deformação tetragonal da rede cristalina das camadas de GaxIn1-xP Abstract: In this work, semiconductor heterostructures with thin GaxIn1-xP layers of different thicknesses, grown on top of GaAs(001) substrates by the technique of Chemical Beam Epitaxy (CBE); were analyzed through rocking curves and x-ray multiple diffraction. From the rocking curves obtained in a double-crystal and also triple-axes systems it was possible to determine the analyzed structure together with the compositions, the perpendicular lattice parameters and, the thicknesses of the layers in each sample. GaAs strained buffer layers as well as the occurrence of thin epitaxial GaAsyP1-y (13 to 20 Þ ) surface layers between the GaxIn1-xP epilayers and the buffer were obtained from the rocking curve simulations with the x-ray dynamical theory program, giving rise to the best match for the experimental curves. The x-ray multiple diffraction technique has bee of great utility in this work since the Renninger scan portions with the BSD peaks, special MD cases in which the secondary beam is propagated parallel to the sample surface, have provided enough sensitivity to detect the hybrids peaks. These peaks correspond to contributions of the different lattices (substrate or layer) in the same Renninger scan. The adjustment of these peaks with the program[19] based on the MD phenomenon has provided to obtain the lattice parameters (substrate and layer) parallel to the interface and the mosaic spread of the GaxIn1-xP layers and of the GaAsyP1-y thin interafce layers, that have already been detected by the rocking curves. Surface topography of all samples were also obtained by atomic force microscopy and it was possible to relate the behavior of the average roughness curves as a function of the layer thickness to the lattice strain, probably caused by the tetragonal distortion of the GaxIn1-xP layer crystalline lattices Mestrado Física Mestre em Física